Carburizer



Patented D... 18, 1928.

UNITED, STATES v I 1,695,337 PATENT OFFICE.

'nnnnnnrcxc. LANGENBERG, or WATERTOWN, mnssacnusn'r'rs, AssIGNon TO 1:. r. HOUGHION AND COMPANY, or PHILADELPHIA, rnnnsynvama, A conronurron OF i PENNSYLVANIA. Y

No Drawing.

My invention relates to that class of compounds known as carburizing or case hardening materials,

One object of my invention is toprovide a new and improved compound which is a.

ceous materials such as charcoal or coke which in themselves have little or no case hardening properties. I Another object of my invention is to provide a relatively cheap carburizing activator ployment, as a carburizing activator or energizer, of a mixture of two types of salts of the metals which have carburizing properties, that is to say, a mixture of two types-of salts of the alkali or alkaline earth groups, particularly sodium,potassium,barium or calcium, hereinafterreferred to throughout the specification and'claims as carburizing oxides or metals. One of the two types of salts which go to make up the mixture here contemplated comprises the salts of the organic acids, such salts being typified by the formate, acetate, oleate, oxalate, citrate, tartrate and the like. The other type ofsalt tobe used in conjunction with the salts of the .organic acids comprises those salts of the alkali or alkaline earth metals whose acid radical contains oxygen and nitrogen, for example the nitrates or nitrites. The salt mixture may be added to a compound having in itself certain carburizing properties, in which case, the addition of the salt will materially-r intensify and accelerate'the carburizing action as well as morease its effectiveness in subsequent runs. The salt mixture may be added to a relatively inert compound, such as coke or charcoal grain, in order to give rially.

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Application filed March 22, 1927. Serial Np. 177,469.

carburizing action to it. In this latter case,

.the resulting compound will be even more effective than the present carburizers of commerce.

The chemical reason for the remarkable action of these salt mixtures as activating and energizing materials is not understood. The presence of the nitrogenoxides together with the carbon dioxide and carbon monoxide freed from the organic salts undoubtedly plays some part and probably the finely di-- Vided condition of the alkali or alkaline earth oxides resulting from the liberation of the gases from each molecule of salt aids mate- As hereinbefore pointed out, however, the exact reason is not understood and this chemical discussion is merely theory and is to be considered as such and not in any way binding upon the invention, which broadly comprises the useas carburizing orener 'zing material of the salt mixture hereinbe ore described. However, it is a fact that when these two types of salts are used conjointly,

a result will be .obtained which will be a striking improvement over the use of any single salt of the classes described.

As hereinbefore pointed out, this new salt mixture may be used as an activator in conjunction with other well known activators, such as sodium, calcium or barium carbonate, .86

to increase the activity and to lengthen the life of the carbu'rizer, or it may be added to the base carbon grains, such as charcoal or coke, in order to render them active as carburizers. In either case, the salt mixture may be added to the charcoal or coke grains inv a wide variety of ways with good results. It is to be understood also that more than one. of each of the salt types may be added at the same time, if desired,

The new activating mixture may be mechanically tumbled in a powdered condition with the grains to be activated until the energizer permeates the grains or becomes frictionally adherent thereto. In this operation, if itis desired, other carburizing compounds may be added to the tumbler. After the tumbling of the grains with the powdered material, a binder such as black strap molasses or hydrocarbon oil may be added to prevent the energizer from dusting off in transit and in use, and the grains may then be treated with a powdered material such as charcoal dust to prevent them from caking. The grains to be activated may be treated with the binder prior to the treatment with the energizerand dust or simultaneously with the binder.

With those COIIIPOIIIIdS'WhlCh are soluble, the energizer may be dissolved in water and the carbonaceous grams mmersed. therein until the solution has been absorbed. This 3 method provides a means for thoroughly mwill be evident to one skilled in the art, for

example, a paste of carbonates, formed by moistening them with a saturated solution of the new compound,' rnight be smeared upon the surface'of the'carbonaceous grains.

The percentage of the salts in the mixture i will depend-on the nature of the material to whichit is applied and the work for which i the carburizer is intended. Ten per cent or even more of each class may be used successfully to render active a relatlvely inactive carbonaceous grain, while five per cent or less will serve to greatly intensify the action of a carburizing compound. Even a. ,salt

mixture comprising one quarter of.one per cent of each salt is suflicient' at times to show marked improvement inthe action of a car- .burizing compound, or to render active inert carbonaceous grains.

A carburizing material was tested under certain conditions and the depth of total case was measured. Percentages of the salt mixture were added to the compound and comparable tests run to ascertain the increase in depth. The following results are merely indicative of the general effect of the case of these activators and depend on many factors. For this reason, they must not be considered entirely comparable eitherto each other or to the results obtained withthe same percent ages of compounds using difierent conditions of operations. The percentages given are for the increasesin the carburizing activity obtained over that of the original carburizer without the addition of the salt mixture 5 Percentage ncrease Compound added over army I nal depth 3% calcium acetate, 2% potassium nitrite-.- 52. 8% 3% calc um acetate, 2% sodium nitrite 3o. 2% 3% calc um acetate, 2% strontium nitrate 28.3% 2% calcium acetate, 3% potassium nitrate 18 9% While these figures are given for calcium acetate, corresponding results are obtained with barium oxalate and other organic salts. Other salts of the nitrates and nitrites also give satisfactory results, for example barium and calcium salts have proved to be excep- -burizing. oxide a1id a salt of a carburizing tionally applicable. The carburi'zing mate.

rial used in the above examples was'finely.

divided spent bone. -The first run in each case was made with the carburizer per so while in the second run the spent bone had been impregnated with the given percen'tages of the compounds. The steel which analyzed carbon 22%,ma1iganese 52%, silients'in the product, since these may be largely varied to suit the-particular work for .w ich ,theharburizr is intended. v

I claim: 1

1..-A .carburizin' material having therein an organic oxygen-containingasalt of a caroxide having nitrogen and oxygen in the aci radical.

2. A carburizing compound comprising carbonaceous material, an organic oxygencontaining salt of a carburizing oxide and a salt of carburizing oxide having nitrogen and oxygen in the acid radical.- c

3. A carburizing compound comprising carbonaceous material, an organic oxygencontaining salt of an alkaline earth. metal and a salt of-a carburizing oxide having nitrogen and oxygen in the acld radical.

' 4. A carburizing compound comprising carbonaceous material, an organic oxygencontaining salt of an alkaline earth metal and a salt of an alkali metal having nitrogen and oxygen in the acid radical. i 5. A carburizing compound comprising carbonaceous material, an organic oxygencontaining calcium salt and a' potassium salt hail ingnitrogen and oxygen in the acid rad ica 6. A carburizing compound having therein carbonaceous material, calcium acetate and potassium nitrite.

7. A carburizing compound having therein charcoal, calcium, acetate and potassium ni- I charcoal, a carburizing carbonate, an organic oxygen-containingsalt of a or rburizing oxide and a salt of a carburizing oxide having nitrogen and oxygen in the acid radical.

10. A carburizing compound comprising charcoal, bariumcarbonate, calcium acetate and potassium nitrite. e

11. A carbu'rizing material-having therein an organic oxygen-containing salt of a carburizing oxide and a salt of a carburizing oxide having nitrogen and oxygen in the acid radical, the percentage of each substance being present in amounts between of 1% and 10%.

12. A carburizing material having therein an organic ox 'gen-cm1taining salt of a carburizing oxide and a salt of a carburizing oxide having nitrogen and oxygen in the acid radical, the percentage of each substance being present in amounts between A of 1% and 3%.

13. A carburizing compound having therein carbonaceous material, approximately 3% of calcium acetate and 2% potassium nitrite.

' FREDERICK o. LANGENBERG. 

